WASHINGTON — Rep. Pat Tiberi said Thursday he will give up his House seat and take a job as president of the Ohio Business Roundtable — a surprise decision for the 16-year congressional veteran.

"While I have not yet determined a final resignation date, I will be leaving Congress by January 31, 2018," the Genoa Township Republican said in a statement Thursday. "I have been presented with an opportunity to lead the Ohio Business Roundtable that will allow me to continue to work on public policy issues impacting Ohioans while also spending more time with my family."

The announcement caught many Republicans off guard, and it set off immediate speculation about who might vie for his central Ohio seat. The low-key lawmaker, first elected in 2000, is a close ally of the GOP leadership. He is a senior member of the House Ways and Means Committee, the chamber's tax-writing panel, and is deeply involved in the Republican push for tax reform.

But Tiberi suffered a political setback in 2015 when he lost a bid to be chairman of that powerful committee to Rep. Kevin Brady, R-Texas, in a close contest. That defeat may have played into his decision to step down now, since he would have to wait several years before he could run for that chairmanship again.

"Leaving Congress is not a decision I take lightly but after a lot of consideration, it is the best one for me, my wife, Denice, and our four wonderful daughters," Tiberi said in his statement Thursday.

Sen. Rob Portman, R-Ohio, said he spoke with Tiberi on Wednesday night about his decision.

"He told me he wants to stay through the end of the year to get tax reform done," Portman said.

Portman said Tiberi, who will turn 55 on Saturday, has talked for a while about wanting to spend more time with his family. He has a 14-year-old daughter and 8-year-old triplets. He also recently lost his mother to cancer.

"If you’ve got a young family, it’s particularly tough" to be in Congress, Portman said.

The Ohio Business Roundtable is a lobbying group for the state's biggest businesses. Its current president, Richard Stoff, who helped to found the group, plans to retire at the end of the year.

Gary R. Heminger, the roundtable's executive committee chairman, said Tiberi's service in Ohio's statehouse and in Congress "have given him a deep insight into the needs of Ohio businesses and the legislative and regulatory matters we face.”

The new job will allow Tiberi to stop his weekly commute to Washington — and to leave the growing rancor and gridlock in Congress behind.

Portman did not directly answer a question about whether the current atmosphere in Washington factored into Tiberi's decision. But Tiberi is a pragmatic conservative who often clashed with the increasingly powerful hard-right forces in his party.

First elected in 2000, Tiberi started his political career as an aide to then-Rep. John Kasich. He was also a key ally of ex-House Speaker John Boehner, R-West Chester, and he often defended Boehner against the ultra-conservative faction in the House GOP conference that helped nudge the former speaker into retirement.

More recently, Tiberi agreed to lead a new House caucus that would serve as the GOP’s “governing wing,” a clear slap at conservatives who have opposed the House Republican leadership on an array of hot-button issues, from health care to spending.

"He knows the wisdom of taking half a loaf when you can’t get the whole loaf and coming back for the rest later," said Rep. Tom Cole, R-Okla. "Pat's always prepared to work with anybody and was probably frustrated with others who couldn’t find a way to do that."

But Cole said Tiberi was probably more motivated by family and financial concerns than political frustrations, especially as he prepares to put four kids through college.

"He could make more money. He could have an easier life and he’s certainly done his share of public service," Cole said.

Portman and others said Tiberi's decision to leave Congress would create a political and policy void.

"It’ll be a loss because he’s well-positioned and well-respected," Portman said. "He’s a great legislator, so I’m going to miss him."

Rep. Steve Stivers, R-Columbus, called Tiberi a "mentor" and said he would "sorely missed by his colleagues on both sides of the aisle."

"Pat Tiberi’s leadership in Congress paved the way for countless conservative reforms that will benefit central Ohio for decades to come," Stivers said in a statement.

Ohio Republican Party leader Jane Timken said Tiberi served the state with "unquestionable integrity and determination."